Wireline Release System

ABSTRACT

A wireline release system may include, but is not limited to: a first housing including an internal body portion defining at least one bore; a second housing operably couplable to the first housing; a wireline tie-off assembly, operably couplable to a wireline cable, disposed at least partially within the bore; an assembly disposed at least partially within the bore; a first mechanical weak point configured to maintain the wireline tie-off assembly at a first position of the bore; and a second mechanical weak point configured to maintain the assembly at a second position of the bore.

PRIORITY

The present application claims priority under 35 U.S.C. 119 to U.S. Provisional Patent Application Ser. No. 63/111,331, filed Nov. 9, 2020, and U.S. Provisional Patent Application Ser. No. 63/168,890, filed Mar. 31, 2021. The subject matter of the priority applications is incorporated herein in its entirety to the extent not inconsistent herewith.

FIELD OF THE INVENTION

The invention relates to a mechanical release system for a set of wireline tools, for example, in the oil and gas industry.

BACKGROUND

Wireline cabling may be employed in various drilling or boring industries (e.g., oil and gas exploration). Such wirelines may provide both support for and communication with various wireline tools connected to and suspended from a wireline. Wireline tools are specially designed instruments lowered into a well bore at an end of a wireline cable. Such wireline tools may be designed to provide any number of particular services, such as evaluation of rock properties, formation pressures, information regarding pore size or fluid identification, perforating, plug setting, or sample recovery. Often, multiple wireline tools may be operably coupled to and serviced by a common wireline cable. During operation, it may be the case that one of those wireline tools may become stuck in a casing or bore hole. However, other wireline tools higher up on the wireline cable may still be able to be retrieved from the bore hole. In such cases, it may be desirable to provide a mechanical release system configured to release those wireline tools below a certain point on a wireline in order to minimize the amount of equipment left in the well. In other cases, tools may become stuck at or above a release tool, in which case it would alternatively be desirable to release the cable from the tools string.

BRIEF DESCRIPTION OF THE DRAWINGS

The numerous advantages of the disclosure may be better understood by those skilled in the art by reference to the accompanying figures in which:

FIG. 1 shows a cross-sectional view of a wireline mechanical release system;

FIG. 2 shows a cross-sectional view of a wireline mechanical release system;

FIG. 3 shows a cross-sectional view of a wireline mechanical release system;

FIG. 4 shows a cross-sectional view of a wireline mechanical release system; and

FIG. 5 shows a perspective view of a wireline mechanical release system.

DETAILED DESCRIPTION

Disclosed is a multi-stage mechanical release system 100 configured to release one or more wireline tools from a wireline in a controlled, stagewise matter.

Referring to FIGS. 1-5, various views of a mechanical release system 100 are shown. The mechanical release system 100 may include one or more of the following components: an upper housing 145 having an body portion 109 including a bore 111 defining at least one viscous fluid chamber 142, a lower housing 126 including at least one wireline tool 150, a lower mechanical weak point 116 (e.g., shear screws 115, an intermediate mechanical weak point 136 (e.g., one or more shear screws 137 coupled to a plug assembly 153 disposed within the bore 111), an upper mechanical weak point 143 (e.g. one or more shear screws 108), a wireline tie-off assembly 113 disposed within the bore 111, a wireline cutter assembly 141, a housing release mechanism 144 configured to couple or release the upper housing 145/body portion 109 to/from the lower housing 126, and one or more viscous fluid dampers 146 configured to control a flow of a viscous fluid 147 within the viscous fluid chamber 142.

The tie-off assembly 113 may be a device that provides a mechanical connection with the wireline 101 sufficient to resist tensile forces applied to the wireline 101 at least up to the tensile strength of a wireline 101 without decoupling. The tie-off assembly 113 may include a body portion and a coupling mechanism configured for attachment to a wireline. For example, the wireline 101 may include steel wires 117/118 consisting of inner and/or outer “armors” or tensile members which may be securely held by an inner tapered cone 119 and/or outer tapered cone 120 inside of the tie-off assembly 113 by a cone retainer plug 121. The insulated conductor 124 the center of the wireline 101 may pass through an aperture 152 at the center of the cone retainer plug 121 of the tie-off assembly 113 and be coupled to a retention plate (not shown) before being attached to the conductor 129 which passes into a sealed wireline tool assembly 148 to the right. The body portion of the tie-off assembly 113 may have an outer diameter dimension that is greater than an outer diameter dimension of the wireline 101 and less than an internal diameter dimension of the bore 111.

After assembly of the components of the mechanical release system 100, the viscous fluid chamber 142 of the mechanical release system 100 may be filled with viscous fluid 147 through the viscous fluid port 102. The viscous fluid 147 will serve to displace most of the air within the housings after assembly of the components of the mechanical release system 100. Excess viscous fluid 147 may be vented through the viscous fluid vent ports 132 in the lower housing 126. The vent ports 132 will also allow equalization of pressure between the inside and outside of the mechanical release system 100 when the mechanical release system 100 is introduced to or removed from external-pressure environments. The viscous fluid 147 can take the form of a grease, wax, gel, polymer, low melting temperature metal alloy, or any other material that can be displaced slowly over time. The viscous fluid 147 may be in a solid state when outside of the well bore, but be capable of extruding through the tortuous path. For example, the viscous fluid 147 may also undergo a phase change from solid to liquid at different operating temperatures and/or pressures. The components of the mechanical release system 100 may be inserted into a housing at the top of a tools string as follows: the wireline cutter assembly 141 may be at the top of the housing with the viscous fluid 147 between the wireline cutter assembly 141 and the mechanical weak point 136, then another viscous fluid chamber 142 may be provided between the mechanical weak point 136 and the tie-off assembly 113. The viscous fluid dampers 146 may create a high resistance flow path between the viscous fluid chamber 142 and the outside of the mechanical release system 100 or another area in the mechanical release system 100. The viscous fluid 147 disposed between the tie-off assembly 113 and the mechanical weak point 116, mechanical weak point 136 and/or the mechanical weak point 143 can be maintained, in situ, by its high viscosity between loose fitting parts or by seals that can be overcome (e.g., leak) once a given hydraulic pressure is applied. The tie-off assembly 113 may serve to create a seal on one end of the viscous fluid chamber 142.

In operation, a tensile force 149 may be applied to the tie-off assembly 113 (e.g., upon the occasion that a wireline tool coupled to the wireline 101 below the mechanical release system 100 becomes stuck) via the wireline 101. Once the breaking/shear strength of a weak point (e.g., mechanical weak point 116, mechanical weak point 136, or mechanical weak point 143), is exceeded, the tie-off assembly 113 may travel along the bore 111 (displacing viscous fluid 147). Typically, the breaking/shear strength of a weak point will be higher than the free hanging weight of the wireline tools below and lower than the ultimate tensile strength of the wireline 101. In typical applications this may be between 500 and 5000 lbf. The mechanical release system 100 may include various types of mechanical weak points including but not limited to: shear screws, shear pins, tensile screws, tensile pins, tensile rope, etc., for retaining the tie-off assembly 113 and/or wireline cutter assembly 141 in place relative to the bore 111 prior to actuation. If pins or screws are used, the strength of a weak point can be set either by the individual screw/pin strengths or by the quantity of screws/pins used to couple the components.

Once the mechanical weak point 116 is overcome, the decoupled components (in this case, the tie-off assembly 113) may be drawn through the bore 111 until such point that an electrical connection between the insulated conductor 124 of the wireline 101 and the conductor 129 (e.g. a tear-drop conductor) of a wireline tool assembly 148 is disconnected from the wireline 101 and, resultingly, from any wireline tools below. For example, upon If the tensile force 149 is maintained, the tie-off assembly 113 will continue to travel through the viscous fluid 147 pushing the viscous fluid 147 through viscous fluid dampers 146 until tie-off assembly 113 engages the mechanical weak point 136. Such displacement-regulated movement of the tie-off assembly 113 may be controlled by the volume of the viscous fluid chamber 142, the viscosity of the viscous fluid 147, and/or the tortuosity of the viscous fluid dampers 146. To achieve a desired rate of translation of the tie-off assembly 113. As an example, an operator may apply high tensile force 149 sufficient to overcome the mechanical weak point 116. Then an additional period of time of sustained application of tensile force 149 (e.g. a force lower than the high force required to overcome the mechanical weak point 116) may need to elapse as the viscous fluid 147 is displaced and a break in electrical communication with the wireline tool 150 is observed at a monitoring system. An operator may then again apply high tensile force 149 sufficient to overcome the mechanical weak point 136 releasing the wireline tools below.

The wireline cutter assembly 141 containing mechanical cutter body 104, mechanical cutter 106, and shear screws 108 may be held in place inside the top sub 103 and the body portion 109. In one embodiment, one or more shear screws 108 may hold the mechanical cutter 106 to the mechanical cutter body 104 and separate them from the wireline 101. The mechanical cutter edges 107 may be selected from one or more forms including flat, coned or collets style cutters. The mechanical cutter edges 107 may also be placed onto a cam that rotates into the wireline 101 as the tie-off assembly 113 is pulled through the mechanical release system 100. The mechanical cutter edges 107 may also take the form of rotating cammed surfaces with eccentric holes.

Referring to FIGS. 1-4, the tie-off assembly 113 is shown at various stages of transit through the bore 111. For reference, tension applied to the wireline 101 will pull the wireline 101 and any attached wireline tools from right to left as depicted in FIGS. 1-4.

Referring to FIG. 1, the mechanical release system 100 is shown with each of mechanical weak point 116, mechanical weak point 136, mechanical weak point 143 (implemented shear screws 115, shear screws 137 and shear screws 108, respectively) intact. The wireline 101 enters into the mechanical release system 100 through a top sub 103. The wireline 101 is shown to terminate just to the left of the mechanical release system 100. In operations, the wireline 101 would be a continuous strand that connects the mechanical release system 100 to a spool on the surface with a reel for pulling and releasing tension and length of the wireline 101 during operations in a well. A standard GO-type connector 130 may be used for the electrical pass through between the wireline 101 and a wireline tool 150 housed within the wireline tool assembly 148.

At least one O-ring 114 may be placed around the tie-off assembly 113 to seal its outer diameter within the bore 111 within the body portion 109 to prevent the viscous fluid 147 from flowing between the outer diameter of the tie-off assembly 113 and the bore 111 after the mechanical weak point 116 is overcome and the tie-off assembly 113 has been pulled along the bore 111. A non-tortuous fluid flow path may be defined in either the wall of the bore 111 or the body of the tie-off assembly 113. For example, one or more longitudinal channels 135 may be cut into the bore 111 and/or the outside of the tie-off assembly 113 to allow a portion of the viscous fluid 147 to bypass the tie-off assembly 113 as it is held in place, relative to the body portion 109, at the mechanical weak point 116. This bypass could also be implemented by increasing a diameter of viscous fluid chamber 142 such that the O-ring 114 does not engage the wall of the bore 111 defining the viscous fluid chamber 142 until the mechanical weak point 116 is overcome and the tie-off assembly 113 is allowed to move inside the bore 111. Alternately, components configured to provide a sealing to at least partially limit flow of viscous fluid 147 within the bore 111 may be integrated into components configured to move relative to the housing when the tie-off assembly 113 is no longer retained in its initial position. In another embodiment, if a very high viscosity viscous fluid 147 is utilized, seals may not be required due to the high pressure drop experienced by moving the tie-off assembly 113 within the bore 111.

Referring to FIG. 2, a cross-sectional view of the mechanical release system 100 depicts a configuration where the mechanical weak point 116 has been overcome. For example, when the tensile force 149 on the wireline 101 exceeds the mechanical weak point strength at the mechanical weak point 116, the shear screws 115 may shear at surface 202A of the tie-off assembly 113 and surface 202B of the bore 111. The tie-off assembly 113 may then travel within the bore 111 and displace enough viscous fluid 147 from the bore 111 that the tie-off assembly 113 may come into contact with the mechanical weak point 136. For example, the viscous fluid 147 may be forced out of the viscous fluid chamber 142 through a tortuous fluid flow path (e.g., through the mutual threading 139 which couples the upper housing 145 and the body portion 109) so as provide a regulated depressurization of the viscous fluid 147 allowing for control of a rate of movement of the tie-off assembly 113. In alternate embodiments, other methods of creating high pressure drops at low flow rates may be employed such as vortex chambers, Da Vinci valves, and the like. As the tie-off assembly 113 moves through the bore 111, the insulated conductor 124 may pull away from the conductor 129 causing the electrical connection to be severed at an endpoint 203 of the insulated conductor 124. This can be done by using a short wire (not shown) between the tie-off assembly 113 and the conductor 129 or other electrical connect (e.g., a plate tie). Disconnection of the insulated conductor 124 from the conductor 129 may result in termination of electrical communication with the wireline tool 150, thereby alerting an operator. Once the tie-off assembly 113 has contacted the mechanical weak point 136 at surface 201, continued tensile force 149 applied to the wireline 101 may apply a shear force to the shear screws 137 of the mechanical weak point 136.

As noted above, a housing release mechanism 144 may be employed to couple the lower housing 126 to the body portion 109 until such time that disconnection of the wireline 101 from wireline tools below occurs. For example, one or more inserts, such as ball bearings 134 may be integrated with the body portion 109, towards the lower housing 126, by insertion through one or more apertures 151 in the body portion 109 and into a one or more internal recesses or an internal circumferential groove 133 in the lower housing 126. The groove 133 may be designed with restrictive portions (e.g., one or more flanges or projections (not shown)) to at least partially to retain the ball bearings 134 within the groove 133 at all times. When the mechanical release system 100 is assembled, the ball bearings 134 may be biased towards the outside of the mechanical release system 100 via interaction with the tie-off assembly 113 at a contact point 140. Positioning of the ball bearings 134 within the groove 133 in the body portion 109/lower housing 126 may retain the ball bearings 134 in place until the tie-off assembly 113 travels along the bore 111 to a point where the ball bearings 134 no longer contact the tie-off assembly 113. In alternate embodiments, the housing release mechanism 144 may include one or more threaded portions and the mechanical weak point 136 may not be utilized if release of tools below the mechanical release system 100 is not desired.

Referring to FIG. 3, continued application of tensile force 149 to the tie-off assembly 113 may overcome the mechanical weak point 136, allowing the tie-off assembly 113 to again slowly progress up into the mechanical weak point 143 and wireline cutter assembly 141. If tensile force 149 is maintained, the tie-off assembly 113 and mechanical weak point 136 will reach the wireline cutter assembly 141 engaging the mechanical weak point 143. Once the tie-off assembly 113 has traveled a sufficient distance within the bore 111, the ball bearings 134 configured to couple the lower housing 126 to the body portion 109 are no longer supported by the tie-off assembly 113 and may at least partially retract into the apertures 151 of the body portion 109 thereby disconnecting the body portion 109 from the lower housing 126 and any wireline tools below. In alternate embodiments, the housing release mechanism 144 may include lugs, dogs, collets, pins, or other releasable locking mechanisms to couple the body portion 109 to the lower housing 126.

Referring to FIG. 4, a cross-sectional view of the mechanical release system 100 depicts a configuration where the mechanical weak point 136 has been overcome and the tensile force 149 has been maintained long enough for the tie-off assembly 113 to settle into contact with the mechanical weak point 143. For example, the shear screws 137 of mechanical weak point 136 have sheared at surface 302A of the bore 111 and surface 302B of the tie-off assembly 113.

Referring to FIG. 5, a cross-sectional view of the portion of the mechanical release system 100 which remains following decoupling of the lower housing 126 and where the tie-off assembly 113 has traveled to its furthest extent within the bore 111.

If continued tensile force 149 is applied to the wireline 101, mechanical weak point 143 between the mechanical cutter 106 and the mechanical cutter body 104 (e.g., shear screws 108) may be been overcome at surface 401A of the mechanical cutter body 104 and surface 401B of the mechanical cutter 106, respectively. Once the mechanical weak point 143 is overcome, it may free the mechanical cutter 106 of the wireline cutter assembly 141 allowing mechanical cutter edges 107 to engage the wireline 101 and sever it from tie-off assembly 113. For example, continued application of tensile force 149 may cause the tie-off assembly 113 and plug assembly 153 to push the mechanical cutter 106 along an tapering surface 105 of the wireline cutter assembly 141 forcing the mechanical cutter edges 107 into the wireline 101 severing it from the tie-off assembly 113 and fully releasing the portion of the wireline 101 above the mechanical release system 100 and any additional wireline tools attached thereto. Once severed from the tie-off assembly 113, the length of wireline 101 (and any coupled wireline tools) above the mechanical release system 100 can then be retrieved from a well.

Different features, variations and multiple different embodiments have been shown and described with various details. What has been described in this application at times in terms of specific embodiments is done for illustrative purposes only and without the intent to limit or suggest that what has been conceived is only one particular embodiment or specific embodiments. It is to be understood that this disclosure is not limited to any single specific embodiments or enumerated variations. Many modifications, variations and other embodiments will come to mind of those skilled in the art, and which are intended to be and are in fact covered by this disclosure. It is indeed intended that the scope of this disclosure should be determined by a proper legal interpretation and construction of the disclosure, including equivalents, as understood by those of skill in the art relying upon the complete disclosure present at the time of filing. The foregoing descriptions of specific embodiments are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed:
 1. A wireline release system comprising: a first housing including an internal body portion defining at least one bore; a second housing operably couplable to the first housing; a wireline tie-off assembly, operably couplable to a wireline cable, disposed at least partially within the bore; an assembly disposed at least partially within the bore; a first mechanical weak point configured to maintain the wireline tie-off assembly at a first position of the bore; and a second mechanical weak point configured to maintain the assembly at a second position of the bore.
 2. The wireline release system of claim 1, wherein the wireline tie-off assembly includes: a body portion having an outer diameter dimension that is greater than an outer diameter dimension of the wireline and less than an internal diameter dimension of the bore.
 3. The wireline release system of claim 1, further comprising: at least a portion of at least one viscous fluid disposed within the bore at least between the wireline tie-off assembly and the assembly.
 4. The wireline release system of claim 3, wherein at least one of the wireline tie-off assembly or the internal body portion defining at least one bore includes: at least one non-tortuous fluid flow path configured to transmit at least a portion of viscous fluid around the tie-off assembly while the tie-off assembly is maintained at the first position to allow for pressure equilibration of the viscous fluid.
 5. The wireline release system of claim 3, further comprising: at least one tortuous fluid flow path configured to transmit at least a portion of the viscous fluid from the bore upon pressurization of the viscous fluid via movement of the wireline tie-off assembly within the bore.
 6. The wireline release system of claim 1, wherein the first mechanical weak point includes: a mechanical weak point having a breaking strength of between 500 and 5000 lbf.
 7. The wireline release system of claim 1, wherein the assembly disposed at least partially within the bore includes: a plug assembly disposed at least partially within the bore.
 8. The wireline release system of claim 7, wherein the second mechanical weak point includes: a mechanical weak point coupling the at least a portion of the internal body and the plug assembly and having a breaking strength of from 500 to 5000 lbf.
 9. The wireline release system of claim 7, wherein the at least a portion of at least one viscous fluid disposed within the bore at least between the wireline tie-off assembly and the plug assembly includes: at least a portion of at least one viscous fluid disposed within the bore at least between the plug assembly and the wireline tie-off assembly.
 10. The wireline release system of claim 1, wherein the assembly disposed at least partially within the bore includes: a wireline cutting assembly.
 11. The wireline release system of claim 10, wherein the wireline cutting assembly includes: at least one tapering surface; and one or more cutting edges configured to engage a wall of the wireline.
 12. The wireline release system of claim 11, wherein the second mechanical weak point includes: a mechanical weak point configured to maintain the one or more cutting edges in a position where they do not contact the wireline.
 13. The wireline release system of claim 12, wherein the mechanical weak point configured to maintain the one or more cutting edges in a position where they do not contact the wireline includes: a mechanical weak point coupling at least a portion of the internal body and the one or more cutting edges and having a breaking strength of from 500 to 5000 lbf.
 14. The wireline release system of claim 10, wherein the at least a portion of at least one viscous fluid disposed within the bore at least between the wireline tie-off assembly and the plug assembly includes: at least a portion of at least one viscous fluid disposed within the bore at least between the wireline cutting assembly and the wireline tie-off assembly.
 15. The wireline release system of claim 10, further comprising: a plug assembly disposed at a third position within the bore between the wireline cutting assembly and the wireline tie-off assembly; and a third mechanical weak point configured to maintain the plug assembly at the third position of the bore.
 16. The wireline release system of claim 15, wherein the third mechanical weak point includes: a mechanical weak point coupling the plug assembly to the internal body and having a breaking strength of from 500 to 5000 lbf.
 17. The wireline release system of claim 15, wherein the at least a portion of at least one viscous fluid disposed within the bore at least between the wireline tie-off assembly and the plug assembly includes: at least a portion of at least one viscous fluid disposed within the bore at least between the wireline tie-off assembly and at least one of the plug assembly and the wireline cutting assembly.
 18. The wireline release system of claim 1, further comprising: a housing release mechanism configured to couple the internal body portion of the first housing and the second housing.
 19. The wireline release system of claim 1, wherein the housing release mechanism includes: at least one recess in the second housing; at least one aperture in the internal body portion; at least one insert.
 20. The wireline release system of claim 19, wherein the insert is disposed at least partially within the recess in the second housing and at least partially within the aperture when the insert is in contact with the wireline tie-off assembly; and wherein the insert retracts out of the recess in the second housing and into the aperture in the internal body portion when the insert is not in contact with the wireline tie-off assembly.
 21. The wireline release system of claim 19, wherein the at least one recess in the second housing includes: at least one internal circumferential groove.
 22. The wireline release system of claim 19, wherein the at least one insert includes: at least one ball bearing.
 23. A method for releasing a wireline comprising: applying a first tensile force to a wireline cable connected to a wireline tie-off assembly sufficient to overcome a first mechanical weak point associated with the wireline tie-off assembly; applying a second tensile force to the wireline cable for a time period sufficient to cause the wireline tie-off to displace a portion of a viscous fluid within a bore; and applying a third tensile force to the wireline cable connected to a wireline tie-off assembly sufficient to overcome a second mechanical weak point. 